Continental Europe is home to more than 125,000 known species of terrestrial and freshwater animal, and each year another 700 newly described species join the list. That sounds like good news to mark the end of 2010, the International Year of Biodiversity. It may not be. The planet buzzes with life, most of it unidentified and an alarming proportion of it now vulnerable to extinction. That is why the UN has declared 2011 to be both the International Year of Forests and the launch of an International Decade of Biodiversity, with a new intergovernmental panel of expertise. French researchers pointed out in November that the inventory of European fauna is incomplete and that they cannot begin to guess what the total might be. Yet Europe is where taxonomy and ecology began: from Beijing to Bradford, from Windhoek to Wisconsin, creatures have formal Latin names because Latin was the scholarly language of the first systematic catalogue of the living world little more than 250 years ago.

Biodiversity is all we have. Living things provide humankind's food, fabric, fibre and pharmaceuticals; they fertilise and pollinate crops, generate oxygen and recycle water. The wealth of nations is built upon biodiversity: even the oil, coal, peat, chalk and flints dug from the ground were once living tissue. So the case for the conservation of life's variety ought to be obvious. But biodiversity is a problem in four parts. We do not know, cannot identify, and cannot even begin to count most of the creatures upon whom we depend; nor do we know how these unidentified species interact with and depend upon each other; yet we are extinguishing this richness at a rate perhaps unparalleled in the 3.5bn year history of life on Earth; and we have as yet no masterplan with which to address any of these challenges.

Right now one fifth of the planet's known vertebrates and one fifth of its named flowering plants are vulnerable, threatened or heading for extinction, but these represent only a small fraction of all that there is to conserve. If biodiversity is still unfinished business in the continent in which research began – and which is still home to most of the world's expertise – then things look ominous for those places so much richer in wildlife and so much poorer not just in money but in scientific investment: those countries with the coral reefs, mangrove swamps, rainforests, savannahs and dry uplands that are home to the greatest diversity.

There are of course vital projects – the Census of Marine Diversity, the Barcode of Life, International Union for Conservation of Nature red lists and so on. But they do not add up to global determination, and so far these initiatives do not address one taxonomic riddle: confusion about how many species have been "discovered" and named more than once. There is a global convention on biological diversity with 193 signatories, which declares that living species are not the common heritage of all mankind; instead states have sovereign rights over their own biological resources, and therefore implicitly a direct interest in conserving them. Since the richest concentrations of biodiversity are held by the poorest nations, scientists from Europe and the US must negotiate formidable bureaucratic and social obstacles before they can begin research, train local naturalists and start to advise on conservation techniques. Such intricacies forced the last-minute cancellation of a London Natural History Museum initiative in Paraguay in November.

Meanwhile, the most conservative estimates suggest that creatures fashioned by millions of years of evolution are being extinguished at a rate a thousand times faster than, for example, at the end of the Ice Age, and that as the human population grows in the next 90 years, this extinction rate is predicted to increase by a further tenfold. Such problems cannot be solved in a year, or a decade. But perhaps, with serious political investment, a concerted global effort can at last begin.